JP7346250B2 - Internal combustion engine system abnormality diagnosis device - Google Patents

Description

The present invention relates to an abnormality diagnosis device for an internal combustion engine system.

For example, a diesel engine system with a turbocharger is known as described in Patent Document 1. This system is equipped with various sensors, such as an air flow sensor that measures the flow rate of gas supplied to the diesel engine, and a boost pressure sensor that detects the boost pressure of gas supplied to the diesel engine.

Here, in the system as described above, it is determined whether or not there is an abnormality in the boost pressure based on the boost pressure sensor value detected by the boost pressure sensor. The presence or absence of an abnormality in the boost pressure cannot be accurately determined if a characteristic abnormality occurs in the boost pressure sensor. Therefore, in the above-mentioned system, it is required to determine not only whether there is an abnormality in the boost pressure but also whether there is an abnormality in the characteristics of the boost pressure sensor. For example, a characteristic abnormality of the boost pressure sensor can be determined by using the detected value of the air flow sensor.

JP2007-023977A

However, in the above-mentioned system, an air flow sensor may not be provided depending on the type of system. In this case, it is not possible to determine whether there is an abnormality in the characteristics of the boost pressure sensor using the detected value of the airflow sensor. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an abnormality diagnosis device for an internal combustion engine system that can determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor without using an airflow sensor. do.

The present invention is an abnormality diagnosis device for diagnosing an abnormality in an internal combustion engine system including an internal combustion engine and a turbocharger, and includes a boost pressure sensor that detects the boost pressure of gas supplied to the internal combustion engine by the turbocharger, and a boost pressure sensor. Boost pressure difference value calculation that calculates the boost pressure difference value, which is the difference between the boost pressure sensor value and the target boost pressure, based on the boost pressure sensor value detected by and the target boost pressure of the gas supplied to the internal combustion engine. , an estimated working gas flow rate which is the flow rate of gas supplied to the internal combustion engine estimated based on the boost pressure sensor value, and an estimated exhaust gas flow rate which is the estimated flow rate of gas exhausted from the internal combustion engine. a gas flow rate difference value calculation unit that calculates a gas flow rate difference value that is the difference between the estimated working gas flow rate and the estimated exhaust gas flow rate; an abnormality determination section that determines whether the boost pressure sensor is overboost or underboost, and determines whether the boost pressure sensor is abnormal in characteristics; If the boost pressure sensor value is smaller than the target boost pressure and the gas flow rate difference value is within the gas flow rate threshold range, it is determined that there is underboost, and the boost pressure difference value is outside the boost pressure threshold range, and the boost If the pressure sensor value is larger than the target boost pressure and the gas flow rate difference value is within the gas flow rate threshold range, it is determined that there is overboost, and the boost pressure difference value is outside the boost pressure threshold range, and the boost pressure sensor value is larger than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is larger than the estimated exhaust gas flow rate, it is determined that an excessive side characteristic abnormality has occurred in the boost pressure sensor, When the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate. , it is determined that the boost pressure sensor has an abnormal characteristic on the under side characteristic.

This abnormality diagnosis device for an internal combustion engine system can determine whether overboost or underboost is present based on the boost pressure difference value and the gas flow rate difference value, and furthermore, the abnormality diagnosis device for the internal combustion engine system can determine whether the overboost is overboost or underboost. can also be determined. That is, since the abnormality diagnosis device for an internal combustion engine system can determine whether there is an abnormality in the characteristics of the boost pressure sensor, it is possible to improve the reliability of the determination result as to whether there is an abnormality in the boost pressure. In this way, the abnormality diagnosis device for an internal combustion engine system can determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor, without using an air flow sensor.

The abnormality diagnosis device for an internal combustion engine system further includes an oxygen concentration sensor that detects the oxygen concentration of gas exhausted from the internal combustion engine, and the estimated exhaust gas flow rate is estimated based on the oxygen concentration sensor value detected by the oxygen concentration sensor. If the boost pressure difference value is within the boost pressure threshold range, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate, the abnormality determination unit detects an excess in the oxygen concentration sensor. If it is determined that a side characteristic abnormality has occurred, the boost pressure difference value is within the boost pressure threshold range, the gas flow rate difference value is outside the gas flow rate threshold range, and the estimated working gas flow rate is greater than the estimated exhaust gas flow rate, It may be determined that the oxygen concentration sensor has a characteristic abnormality on the low side. In this way, the abnormality diagnosis device for an internal combustion engine system can also determine whether there is a characteristic abnormality in the oxygen concentration sensor used to estimate the estimated exhaust gas flow rate.

The internal combustion engine system abnormality diagnosis device uses an atmospheric pressure sensor that detects atmospheric pressure, and the no-load boost pressure sensor value detected by the boost pressure sensor when fuel is not injected into the internal combustion engine. and a no-load pressure difference value calculation unit that calculates a no-load pressure difference value that is a difference between the detected atmospheric pressure sensor value and the detected atmospheric pressure sensor value; If the boost pressure sensor value is smaller than the target boost pressure, the gas flow rate difference value is within the gas flow rate threshold range, and the no-load pressure difference value is within the no-load pressure threshold range, it is determined that there is underboost. However, the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is greater than the target boost pressure, the gas flow rate difference value is within the gas flow rate threshold range, and the no-load pressure difference value is at no-load. If it is within the pressure threshold range, it is determined that there is overboost, the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is greater than the target boost pressure, and the gas flow rate difference value is within the gas flow threshold range. , the estimated working gas flow rate is greater than the estimated exhaust gas flow rate, the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is greater than the atmospheric pressure sensor value, It is determined that the boost pressure sensor has an excessive characteristic abnormality, the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, and the gas flow rate difference value is outside the gas flow threshold range. , the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate, the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is smaller than the atmospheric pressure sensor value. It may be determined that the boost pressure sensor has an abnormal characteristic on the under side characteristic. In this case, by using the no-load pressure difference value, the abnormality diagnosis device for the internal combustion engine system can more accurately determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor.

In an abnormality diagnosis device for an internal combustion engine system, the abnormality determination unit determines whether the gas flow rate difference value is within the gas flow rate difference value, the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor If the value is smaller than the atmospheric pressure sensor value, it is determined that the atmospheric pressure sensor has an abnormal characteristic on the excessive side, and the gas flow rate difference value is within the gas flow rate difference value, and the no-load pressure difference value is determined to be at no-load. If it is outside the pressure threshold range and the no-load boost pressure sensor value is larger than the atmospheric pressure sensor value, it may be determined that the atmospheric pressure sensor has an abnormal characteristic on the under side characteristic. In this manner, the abnormality diagnosis device for an internal combustion engine system can also determine whether there is a characteristic abnormality in the atmospheric pressure sensor used to calculate the no-load pressure difference value.

According to the present invention, it is possible to determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor without using an air flow sensor.

FIG. 1 is a diagram showing a schematic configuration of an abnormality diagnosis device and an engine system according to an embodiment. FIG. 2 is a block diagram showing the functional configuration of the abnormality diagnosis device. FIG. 3 is a diagram showing an abnormal characteristic of the sensor. FIG. 4 is a table showing the correspondence between various abnormalities occurring in the engine system and boost pressure difference values.

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same or corresponding elements are given the same reference numerals, and redundant description will be omitted.

As shown in FIG. 1, an abnormality diagnosis device 10 diagnoses abnormalities in an engine system (internal combustion engine system) 1 that includes a diesel engine 2 as an internal combustion engine and a turbocharger 3. The engine system 1 is mounted on a vehicle such as a truck.

More specifically, the engine system 1 includes a diesel engine 2, a turbocharger 3, an intercooler 4, and a urea SCR system 5. The turbocharger 3 operates a compressor using exhaust gas discharged from the diesel engine 2, and pressurizes the gas (air) supplied to the diesel engine 2. Gas pressurized by the turbocharger 3 is cooled in an intercooler 4 and supplied to the diesel engine 2. The urea SCR system 5 purifies exhaust gas discharged from the diesel engine 2. The urea SCR system 5 reduces NOx contained in exhaust gas using, for example, urea water added on the upstream side.

The abnormality diagnosis device 10 diagnoses abnormalities in the engine system 1 and the like. The abnormality diagnosis device 10 includes an abnormality diagnosis unit 6, a boost pressure sensor S1, an intake temperature sensor S2, an engine rotation sensor S3, an oxygen concentration sensor S4, and an atmospheric pressure sensor S5.

Boost pressure sensor S1 detects the boost pressure of gas pressurized by turbocharger 3 and supplied to diesel engine 2. The intake air temperature sensor S2 detects the temperature of gas (intake air temperature) supplied to the diesel engine 2. The intake temperature sensor S2 is provided, for example, in the intake manifold of the diesel engine 2.

Engine rotation sensor S3 detects the number of rotations (number of rotations per unit time: rotational speed) of the diesel engine 2. Oxygen concentration sensor S4 detects the oxygen concentration of gas exhausted from diesel engine 2. The oxygen concentration sensor S4 is provided in the exhaust path between the turbocharger 3 and the urea SCR system 5. Atmospheric pressure sensor S5 detects the atmospheric pressure around diesel engine 2.

The abnormality diagnosis unit 6 determines the presence or absence of various abnormalities based on the detection results of the boost pressure sensor S1 to the atmospheric pressure sensor S5. The abnormality diagnosis unit 6 is an electronic control unit having, for example, a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], a CAN [Controller Area Network] communication circuit, and the like. The abnormality diagnosis unit 6 loads programs stored in the ROM into the RAM, and executes the programs loaded into the RAM by the CPU, thereby realizing various functions.

As shown in FIG. 2, the abnormality diagnosis unit 6 functionally includes a boost pressure difference value calculation section 11, a gas flow rate difference value calculation section 12, a no-load pressure difference value calculation section 13, and an abnormality determination section 14. It is equipped with

The boost pressure difference value calculation unit 11 calculates the difference between the boost pressure sensor value and the target boost pressure based on the boost pressure sensor value detected by the boost pressure sensor S1 and the target boost pressure of the gas supplied to the diesel engine 2. A boost pressure difference value A is calculated.

Here, the boost pressure difference value calculation unit 11 can acquire the target boost pressure from an engine control unit (not shown) that controls the diesel engine 2, for example. For example, the engine control unit can determine the target boost pressure based on a map showing the relationship between engine speed and fuel injection amount.

In this embodiment, the boost pressure difference value calculation unit 11 calculates the boost pressure difference value A based on the following equation (1).
Boost pressure difference value A = boost pressure sensor value - target boost pressure...(1)

Based on the estimated working gas flow rate, which is the flow rate of gas supplied to the diesel engine 2, and the estimated exhaust gas flow rate, which is the estimated flow rate of gas discharged from the diesel engine 2, the gas flow rate difference value calculation unit 12 calculates the following: A gas flow rate difference value B, which is the difference between the estimated working gas flow rate and the estimated exhaust gas flow rate, is calculated.

Here, the gas flow rate difference value calculation unit 12 can estimate the estimated working gas flow rate based on a well-known method based on the boost pressure sensor value detected by the boost pressure sensor S1. Specifically, for example, the gas flow rate difference value calculation unit 12 uses the boost pressure sensor value, the intake air temperature detected by the intake air temperature sensor S2, and the engine rotation speed detected by the engine rotation sensor S3, Estimated gas flow rate can be estimated.

なお、上記式（２）において、指示燃料噴射量は、エンジン制御ユニットがインジェクタに対して指示する燃料の噴射量である。 Further, the gas flow rate difference value calculation unit 12 can estimate the estimated exhaust gas flow rate based on a well-known method. For example, the gas flow rate difference value calculation unit 12 can estimate the estimated exhaust gas flow rate based on the oxygen concentration sensor value detected by the oxygen concentration sensor S4. More specifically, for example, the gas flow rate difference value calculation unit 12 can estimate the estimated exhaust gas flow rate based on the following equation (2).

Note that in the above equation (2), the instructed fuel injection amount is the fuel injection amount that the engine control unit instructs to the injector.

In this embodiment, the gas flow rate difference value calculation unit 12 calculates the gas flow rate difference value B based on the following equation (3).
Gas flow rate difference value B = Estimated working gas flow rate - Estimated exhaust gas flow rate...(3)

The no-load pressure difference value calculation unit 13 calculates the no-load pressure difference value C, which is the difference between the no-load boost pressure sensor value and the atmospheric pressure sensor value detected by the atmospheric pressure sensor S5. The no-load boost pressure sensor value is a detection value detected by the boost pressure sensor S1 when fuel is not injected into the cylinder of the diesel engine 2.

In this embodiment, the no-load pressure difference value calculation unit 13 calculates the no-load pressure difference value C based on the following equation (4).
No-load pressure difference value C=
No-load boost pressure sensor value - Atmospheric pressure sensor value...(4)

The abnormality determination unit 14 determines whether the gas supplied to the diesel engine 2 is overboost or underboost based on the boost pressure difference value A and the gas flow rate difference value B, and the boost pressure sensor S1 Determine the characteristic abnormality of.

Note that overboost here refers to a state in which the boost pressure of the gas supplied to the diesel engine 2 is higher than the target boost pressure. Underboost is a state in which the boost pressure of the gas supplied to the diesel engine 2 is lower than the target boost pressure. As shown in FIG. 3, the determination of characteristic abnormality of the boost pressure sensor S1 refers to determining whether the detected sensor value deviates from the actual value (actual value) to the excessive side or to the insufficient side. It is. The same applies to the determination of characteristic abnormalities of other sensors described below.

More specifically, as shown in FIG. 4, when the boost pressure difference value A is within the boost pressure threshold range AX and the gas flow rate difference value B is within the gas flow rate threshold range BX, the abnormality determination unit 14 determines that, as shown in FIG. It is determined that each part of the engine system 1 etc. is normal. Further, the abnormality determination unit 14 determines that the boost pressure difference value A is within the boost pressure threshold range AX, the gas flow rate difference value B is within the gas flow rate threshold range BX, and the no-load pressure difference value C is the no-load pressure If it is within the threshold range CX, it can also be determined that each part of the engine system 1 etc. is normal.

Note that the boost pressure threshold range AX, gas flow rate threshold range BX, and no-load pressure threshold range CX are each set in advance. The lower limit of the boost pressure threshold range AX is set to a negative boost pressure threshold A1, and the upper limit of the boost pressure threshold range AX is set to a positive boost pressure threshold A2. The lower limit of the gas flow rate threshold range BX is the gas flow rate negative threshold B1, and the upper limit of the gas flow rate threshold range BX is the gas flow rate positive threshold B2. The lower limit of the no-load pressure threshold range CX is the no-load negative pressure threshold C1, and the upper limit of the no-load pressure threshold range CX is the no-load positive pressure threshold C2.

Further, the abnormality determining unit 14 determines whether the boost is underboost or overboost. Specifically, the abnormality determining unit 14 determines whether the boost pressure difference value A is outside the boost pressure threshold range AX, and the boost pressure If the sensor value is smaller than the target boost pressure and the gas flow rate difference value B is within the gas flow rate threshold range BX, it is determined that there is underboost. That is, the abnormality determination unit 14 determines that there is underboost when the boost pressure difference value A is less than the boost pressure negative threshold A1 and the gas flow rate difference value B is within the gas flow rate threshold range BX.

On the other hand, the abnormality determination unit 14 determines that when the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is larger than the target boost pressure, and the gas flow rate difference value B is within the gas flow rate threshold range BX. , it is determined that there is an overboost. That is, the abnormality determination unit 14 determines that there is an overboost when the boost pressure difference value A exceeds the boost pressure positive threshold value A2 and the gas flow rate difference value B is within the gas flow rate threshold range BX.

Further, the abnormality determination unit 14 determines whether there is an abnormality in the characteristics of the boost pressure sensor S1. Specifically, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is larger than the target boost pressure, and the gas flow rate difference value B is outside the gas flow rate threshold range BX. If the estimated working gas flow rate is larger than the estimated exhaust gas flow rate, it is determined that an excessive side characteristic abnormality has occurred in the boost pressure sensor S1. That is, when the boost pressure difference value A exceeds the boost pressure positive threshold value A2 and the gas flow rate difference value B exceeds the gas flow rate positive threshold value B2, the abnormality determination unit 14 determines that the boost pressure sensor S1 has an excessive side characteristic abnormality. It is determined that this has occurred.

On the other hand, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is smaller than the target boost pressure, and the gas flow rate difference value B is outside the gas flow rate threshold range BX, If the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate, it is determined that the boost pressure sensor S1 has an abnormal characteristic on the under side characteristic. That is, when the boost pressure difference value A is less than the boost pressure negative threshold value A1 and the gas flow rate difference value B is less than the gas flow rate negative threshold value B1, the abnormality determination unit 14 determines that the boost pressure sensor S1 has an abnormal characteristic on the under side. It is determined that the

In this way, the abnormality diagnosis device 10 can determine whether it is overboost or underboost based on the boost pressure difference value A and the gas flow rate difference value B, and furthermore, the abnormality diagnosis device 10 can determine whether it is overboost or underboost. Characteristic abnormalities can also be determined. That is, the abnormality diagnosis device 10 can determine whether there is an abnormality in the characteristics of the boost pressure sensor S1, and therefore can improve the reliability of the determination result as to whether or not there is an abnormality in the boost pressure. In this way, the abnormality diagnosis device 10 can determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor S1 without using an air flow sensor.

Furthermore, in the above description, a configuration has been described in which overboost or underboost and characteristic abnormality of the boost pressure sensor S1 are determined based on the boost pressure difference value A and the gas flow rate difference value B. In addition to the boost pressure difference value A and the gas flow rate difference value B, the abnormality determination unit 14 determines overboost or underboost, and determines whether there is an abnormality in the characteristics of the boost pressure sensor S1, based on the no-load pressure difference value C. It is also possible to judge.

Specifically, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is smaller than the target boost pressure, and the gas flow rate difference value B is within the gas flow rate threshold range BX. If the no-load pressure difference value C is within the no-load pressure threshold range CX, it is determined that underboost is present. That is, the abnormality determination unit 14 determines that the boost pressure difference value A is less than the boost pressure negative threshold A1, the gas flow rate difference value B is within the gas flow rate threshold range BX, and the no-load pressure difference value C is the no-load pressure. If it is within the threshold range CX, it is determined that there is underboost.

On the other hand, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is larger than the target boost pressure, and the gas flow rate difference value B is within the gas flow rate threshold range BX, If the no-load pressure difference value C is within the no-load pressure threshold range CX, it is determined that overboost is present. That is, the abnormality determination unit 14 determines that the boost pressure difference value A exceeds the boost pressure positive threshold A2, the gas flow rate difference value B is within the gas flow rate threshold range BX, and the no-load pressure difference value C is no-load. If it is within the pressure threshold range CX, it is determined that there is overboost.

Further, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is larger than the target boost pressure, and the gas flow rate difference value B is outside the gas flow rate threshold range BX, If the estimated working gas flow rate is greater than the estimated exhaust gas flow rate, the no-load pressure difference value C is outside the no-load pressure threshold range CX, and the no-load boost pressure sensor value is greater than the atmospheric pressure sensor value, the boost pressure It is determined that an abnormal characteristic on the excessive side has occurred in the sensor S1. That is, the abnormality determination unit 14 determines that the boost pressure difference value A exceeds the boost pressure positive threshold value A2, the gas flow rate difference value B exceeds the gas flow rate positive threshold value B2, and the no-load pressure difference value C exceeds the no-load state. If the current pressure exceeds the positive threshold value C2, it is determined that the boost pressure sensor S1 has an abnormal characteristic on the excessive side.

On the other hand, the abnormality determination unit 14 determines that the boost pressure difference value A is outside the boost pressure threshold range AX, the boost pressure sensor value is smaller than the target boost pressure, and the gas flow rate difference value B is outside the gas flow rate threshold range BX, If the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate, the no-load pressure difference value C is outside the no-load pressure threshold range CX, and the no-load boost pressure sensor value is smaller than the atmospheric pressure sensor value, the boost pressure It is determined that the sensor S1 has an abnormal characteristic on the under side characteristic. That is, the abnormality determination unit 14 determines that the engine system 1 is less than the negative boost pressure threshold A1, the gas flow rate difference value B is less than the negative gas flow rate threshold B1, and the no-load pressure difference value C is less than the no-load pressure negative threshold. If it is less than C1, it is determined that the boost pressure sensor S1 has an abnormal characteristic on the under side characteristic.

In this way, by further using the no-load pressure difference value C, the abnormality diagnosis device 10 can more accurately determine whether there is an abnormality in the boost pressure and whether there is an abnormality in the characteristics of the boost pressure sensor S1.

Further, the abnormality determination unit 14 can determine whether the oxygen concentration sensor S4 has a characteristic abnormality. Specifically, the abnormality determination unit 14 determines that the boost pressure difference value A is within the boost pressure threshold range AX, the gas flow rate difference value B is outside the gas flow rate threshold range BX, and the estimated working gas flow rate is lower than the estimated exhaust gas flow rate. If the oxygen concentration sensor S4 is also small, it is determined that an abnormal characteristic on the excessive side has occurred in the oxygen concentration sensor S4. That is, the abnormality determination unit 14 determines that when the boost pressure difference value A is within the boost pressure threshold range AX and the gas flow rate difference value B is less than the gas flow rate negative threshold value B1, an excessive side characteristic abnormality occurs in the oxygen concentration sensor S4. It is determined that the

On the other hand, the abnormality determination unit 14 determines that when the boost pressure difference value A is within the boost pressure threshold range AX, the gas flow rate difference value B is outside the gas flow rate threshold range BX, and the estimated working gas flow rate is larger than the estimated exhaust gas flow rate. , it is determined that the oxygen concentration sensor S4 has a characteristic abnormality on the under side characteristic. That is, when the boost pressure difference value A is within the boost pressure threshold range AX and the gas flow rate difference value B exceeds the gas flow rate positive threshold value B2, the abnormality determination unit 14 determines that the oxygen concentration sensor S4 has an abnormality in the characteristic on the under side. It is determined that this has occurred.

Note that the flow rate of exhaust gas discharged from the diesel engine 2 has an indefinite value when no fuel is injected. Therefore, the abnormality determination unit 14 does not ask for (does not use) the no-load pressure difference value C when determining the characteristic abnormality of the oxygen concentration sensor S4.

In this way, the abnormality diagnosis device 10 can also determine the presence or absence of a characteristic abnormality in the oxygen concentration sensor S4 used for estimating the estimated exhaust gas flow rate.

Further, the abnormality determination unit 14 can determine abnormality in characteristics of the atmospheric pressure sensor S5. Specifically, the abnormality determination unit 14 determines that the gas flow rate difference value B is within the gas flow rate threshold range BX, the no-load pressure difference value C is outside the no-load pressure threshold range CX, and the no-load boost pressure If the sensor value is smaller than the atmospheric pressure sensor value, it is determined that the excessive characteristic abnormality has occurred in the atmospheric pressure sensor S5. That is, when the gas flow rate difference value B is within the gas flow rate threshold range BX and the no-load pressure difference value C is less than the no-load pressure negative threshold value C1, the abnormality determination unit 14 determines that the atmospheric pressure sensor S5 is set to the excessive side. It is determined that a characteristic abnormality has occurred.

On the other hand, the abnormality determination unit 14 determines that the gas flow rate difference value B is within the gas flow rate threshold range BX, the no-load pressure difference value C is outside the no-load pressure threshold range CX, and the no-load boost pressure sensor value is If it is larger than the atmospheric pressure sensor value, it is determined that the atmospheric pressure sensor S5 has a characteristic abnormality on the under side characteristic. That is, when the gas flow rate difference value B is within the gas flow rate threshold range BX and the no-load pressure difference value C exceeds the no-load pressure positive threshold value C2, the abnormality determination unit 14 determines that the atmospheric pressure sensor S5 has an insufficient value. It is determined that an abnormality in side characteristics has occurred.

Note that the target boost pressure is affected by atmospheric pressure. Therefore, the abnormality determination unit 14 does not ask for (does not use) the boost pressure difference value A when determining the characteristic abnormality of the atmospheric pressure sensor S5.

In this way, the abnormality diagnosis device 10 can also determine the presence or absence of a characteristic abnormality in the atmospheric pressure sensor S5 used to calculate the no-load pressure difference value C.

As described above, the abnormality diagnosis device 10 uses the boost pressure difference value A, the gas flow rate difference value B, and the no-load pressure difference value C, as shown in FIG. It is possible to determine whether there is an abnormality.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the boost pressure difference value A may be calculated by "target boost pressure - boost pressure sensor value" as a modification. In this case, the above-described determination may be performed by reversing the positive and negative signs of the boost pressure negative threshold A1 (negative threshold A1) and the boost pressure positive threshold A2 (positive threshold A2) shown in FIG. 4, respectively. The gas flow rate difference value B and the no-load pressure difference value C may also be the same as the modified example of the boost pressure difference value A.

The configuration of the engine system 1 is not limited to the configuration shown in FIG. 1. For example, the engine system 1 may include an EGR unit that recirculates part of the exhaust gas as EGR (exhaust gas recirculation) gas.

Further, the engine system 1 is not limited to having the diesel engine 2 as an internal combustion engine. For example, the engine system 1 may include an internal combustion engine other than the diesel engine 2, such as a gasoline engine or a gas turbine. The abnormality diagnosis device 10 may diagnose various abnormalities in the engine system 1 including an internal combustion engine other than the diesel engine 2.

At least some of the embodiments and various modifications described above may be combined arbitrarily.

DESCRIPTION OF SYMBOLS 1... Engine system (internal combustion engine system), 2... Diesel engine (internal combustion engine), 3... Turbocharger, 4... Intercooler, 5... Urea SCR system, 6... Abnormality diagnosis unit, 10... Abnormality diagnosis device, 11... Boost Pressure difference value calculation section, 12... Gas flow rate difference value calculation section, 13... No-load pressure difference value calculation section, 14... Abnormality determination section, S1... Boost pressure sensor, S2... Intake temperature sensor, S3... Engine rotation sensor, S4...Oxygen concentration sensor, S5...Atmospheric pressure sensor.

Claims (4)

An abnormality diagnosis device for diagnosing abnormalities in an internal combustion engine system including an internal combustion engine and a turbocharger,
a boost pressure sensor that detects the boost pressure of gas supplied to the internal combustion engine by the turbocharger;
an oxygen concentration sensor that detects the oxygen concentration of gas exhausted from the internal combustion engine;
Based on the boost pressure sensor value detected by the boost pressure sensor and a target boost pressure of gas supplied to the internal combustion engine, a boost pressure difference value that is the difference between the boost pressure sensor value and the target boost pressure is determined. a boost pressure difference value calculation unit that calculates;
The estimated working gas flow rate is based on the estimated working gas flow rate, which is the estimated flow rate of gas supplied to the internal combustion engine, and the estimated exhaust gas flow rate, which is the estimated flow rate of gas exhausted from the internal combustion engine. and a gas flow rate difference value calculation unit that calculates a gas flow rate difference value that is the difference between the estimated exhaust gas flow rate and the estimated exhaust gas flow rate;
Based on the boost pressure difference value and the gas flow rate difference value, it is determined whether the gas supplied to the internal combustion engine is overboost or underboost, and a characteristic abnormality of the boost pressure sensor is determined. An abnormality determination section;
Equipped with
The gas flow rate difference value calculation unit includes:
Estimating the estimated working gas flow rate based on the boost pressure sensor value, the intake temperature of the gas supplied to the internal combustion engine, and the engine rotation speed that is the rotation speed of the internal combustion engine,
an oxygen concentration sensor value detected by the oxygen concentration sensor, an air oxygen concentration that is the oxygen concentration of gas supplied to the internal combustion engine, a commanded fuel injection amount instructed to an injector of the internal combustion engine, and a fuel density; and estimating the estimated exhaust gas flow rate based on the stoichiometric mixing ratio,
The abnormality determination unit includes:
If the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, and the gas flow rate difference value is within the gas flow threshold range, it is determined that the underboost is present. death,
If the boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is greater than the target boost pressure, and the gas flow rate difference value is within the gas flow threshold range, the boost is overboosted. It is determined that
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is greater than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is If it is larger than the estimated exhaust gas flow rate, it is determined that an excessive side characteristic abnormality has occurred in the boost pressure sensor,
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is An abnormality diagnosis device for an internal combustion engine system, which determines that an undercharacteristic abnormality has occurred in the boost pressure sensor when the flow rate is smaller than the estimated exhaust gas flow rate. The abnormality determination unit includes:
If the boost pressure difference value is within the boost pressure threshold range, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is smaller than the estimated exhaust gas flow rate, the oxygen concentration sensor It is determined that an abnormal characteristic on the excessive side has occurred,
If the boost pressure difference value is within the boost pressure threshold range, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is greater than the estimated exhaust gas flow rate, the oxygen concentration sensor The abnormality diagnosis device for an internal combustion engine system according to claim 1, which determines that an abnormality in characteristics on the under side characteristic has occurred. An atmospheric pressure sensor that detects atmospheric pressure;
a no-load pressure difference that is the difference between a no-load boost pressure sensor value detected by the boost pressure sensor when fuel is not injected to the internal combustion engine and an atmospheric pressure sensor value detected by the atmospheric pressure sensor; further comprising: a no-load pressure difference value calculation unit that calculates the value;
The abnormality determination unit includes:
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, the gas flow rate difference value is within the gas flow rate threshold range, and the no-load pressure difference If the value is within the no-load pressure threshold range, it is determined that the underboost is present,
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is larger than the target boost pressure, the gas flow rate difference value is within the gas flow rate threshold range, and the no-load pressure difference If the value is within the no-load pressure threshold range, it is determined that the overboost is present,
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is greater than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is greater than the estimated exhaust gas flow rate, the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is greater than the atmospheric pressure sensor value, the boost pressure sensor It is determined that an excessive side characteristic abnormality has occurred in
The boost pressure difference value is outside the boost pressure threshold range, the boost pressure sensor value is smaller than the target boost pressure, the gas flow rate difference value is outside the gas flow threshold range, and the estimated working gas flow rate is is smaller than the estimated exhaust gas flow rate, the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is smaller than the atmospheric pressure sensor value, the boost pressure sensor The abnormality diagnosis device for an internal combustion engine system according to claim 1 or 2, wherein the abnormality diagnosis device for an internal combustion engine system determines that an abnormality in characteristics on the under side has occurred. The abnormality determination unit includes:
The gas flow rate difference value is within the gas flow rate threshold range , the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is greater than the atmospheric pressure sensor value. If the atmospheric pressure sensor is small, it is determined that an abnormal characteristic on the excessive side has occurred in the atmospheric pressure sensor,
The gas flow rate difference value is within the gas flow rate threshold range , the no-load pressure difference value is outside the no-load pressure threshold range, and the no-load boost pressure sensor value is greater than the atmospheric pressure sensor value. 4. The abnormality diagnosis device for an internal combustion engine system according to claim 3, wherein if the atmospheric pressure sensor is large, it is determined that an undercharacteristic abnormality has occurred in the atmospheric pressure sensor.

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